In Vitro Preventive Effect and Mechanism of Action of Weissella cibaria CMU against Streptococcus mutans Biofilm Formation and Periodontal Pathogens

In this study, we evaluated the in vitro anti-biofilm, antibacterial, and anti-inflammatory activity of Weissella cibaria CMU (CMU), an oral probiotic, against periodontopathogens. Compared to other oral probiotics, CMU showed a superior inhibitory effect on the biofilm formation and growth of Streptococcus mutans on orthodontic wires and artificial teeth (p < 0.05). CMU exerted potent antibacterial effects against S. mutans and Porphyromonas gingivalis according to a line test. In human gingival fibroblasts (HGFs) stimulated by P. gingivalis, Fusobacterium nucleatum, or Prevotella intermedia, CMU suppressed the gene expression of pro-inflammatory cytokines [interleukin (IL)-6, IL-1β, IL-8, and tumor necrosis factor-α] in a dose-dependent manner (p < 0.05). CMU restored the production of the tissue inhibitor of metalloproteinase-1 following its inhibition by P. gingivalis, and it suppressed the expression of matrix metalloproteinase (MMP)-1 and -3 induced by periodontopathogens (p < 0.05). Moreover, CMU needed direct contact with HGFs to exert their anti-inflammatory function, indicating that they act directly on gingival cells to modulate local inflammation. Our preclinical study provides evidence for the potential benefits of topical CMU treatments in preventing the development of caries and periodontitis caused by the dysbiosis of the dental plaque microbiome.

The Impact of Smoking on Subgingival Plaque and the Development of Periodontitis: A Literature Review

Smoking seriously affects oral health and causes a variety of oral diseases. Numerous clinical data show that smoking significantly increases the risk of periodontitis, and the duration and amount of smoking are positively correlated with the severity of periodontitis. In fact, smoking creates an environment conducive to the colonization of periodontopathogens, which affects the process of periodontitis. Since subgingival plaque which harbors periodontopathogens is the initiation factor of periodontitis, it is critical to study the impact of smoking on subgingival microbiota for understanding the relationship between smoking and periodontitis. Continuous advances have been made on the understanding of effects of smoking on subgingival plaque and the development of periodontitis. Smoking is observed to enhance the pathogenicity of periodontopathogens, especially the red complex microorganisms, via promoting their colonization and infection, and regulating the expression and function of multiple virulence factors. Furthermore, smoking has a negative impact on periodontal microecological homeostasis, which is reflected in the decrease of commensal bacteria and the increase of periodontopathogens, as well as the changes in the interaction between periodontopathogens and their commensal microbes in subgingival biofilm, thus influencing the pathogenicity of the subgingival plaque. In summary, the mechanism of smoking on subgingival plaque microorganisms represented by the red complex and its effect on the periodontal microecology still need to be further explored. The relevant research results are of great significance for guiding the periodontal clinical treatment of smoking population. This review summarizes the effects and relevant mechanisms of smoking on subgingival plaque and the development of periodontitis.

Membrane vesicles from periodontal pathogens and their potential roles in periodontal disease and systemic illnesses

Periodontium is an ordered ecological system where a dynamic equilibrium exists between oral microorganisms and the host defense system, and periodontal disease occurs whenever the balance is broken. Periodontal pathogens mainly include gram-negative anaerobic bacteria and emerging gram-positive microbes, which have a large variety of virulence factors and influence disease initiation and progression. Recently, different types of bacterial membrane vesicles (MVs), formed by bubbling of membrane materials from living cells or in conditions of endolysin-triggered cell death, have gained interests as a novel virulence factor for periodontopathogens. MVs load multiple sorted cargo molecules, such as proteins, lipids, and genetic materials, and actively participate in toxin transport, signal delivery, and periodontal disease pathogenesis. Since periodontitis is recognized as a risk factor for many systemic diseases, periodontal MVs could work as a bridge for periodontal diseases and systemic illnesses. Furthermore, MVs with unique nature and advantages are promising candidates as vaccines and drug delivery vehicles. In this review, we provided an overview of different types and compositions of periodontal MVs, described their involvements in the pathogenesis of periodontitis and several general diseases, and discussed potential applications of periodontal MVs in vaccination and drug delivery.